tommymonza

Thinking about flipping over the little 19 foot hotrod soon .

The bottom is painted and looks like hell and needs to be stripped and regelled ,so as long as we are upside down maybe adding a variable deadrise pad with shingled multiple steps in it.

The bottom of it already has a very soft rounded keel the last couple feet very similar to the 18 Donzi.

Going to raise the X up 2 1/2 as this is as high as I can get with out having to cut the rubrail for the CMIs.

So I could maybe add another 1/2 inch of pad to the bottom and end the pad 6 inches short of the transom giving me a small notch and leaving me with 3 inches less X overall.

But what I thought would be really interesting would be building into the pad multiple small steps maybe like 6 or 7 with a rise of just a 1/4 inch Kinda like the shingles steps they used to do on the old racers of the 20s.

Runnig 58 stock 260 with Alpha . Going to a 325 with raised X hoping for 70.

Shingled pad maybe good for 5 to 8 mph. If it doesn't work could always grind the steps off and go with just the pad

Interesting speed comparison from back in the day and some good reading.http://www.vintageraceboatshop.com/S...HullDesign.htm

Too Stroked

Since you asked, I'll offer one man's opinion. Major boat manufacturers took some pretty sweet handling hulls and ruined them by adding steps back in the early 2000's. It took many, many iterations to stomp out most (but not all) of the step induced handling evils. Meanwhile, many folks got stuck with some pretty nasty handling boats. Oh yea, but the did go fast in a straight line. And all of this was done by supposedly "experienced" hull designers. And you want to try this one on your own?

And so I ask you in my very best Dirty Harry voice, "So kid, are you feeling lucky?"

tommymonza

A little background.

My older brother originally designed and built the boats and it is a good handling boat as it stands other than it can dance a bit on the rounded keel sometimes .

Years ago I had ridden in and raced against the old 21 Scarabs from the 80's that had a pad on them.

They were 3 feet longer and a little heavier but the pad made up for it with lift and less wetted surface so they were subsequently a few mph faster than my 19 with exact 260 Merc power.

The pad was fairly easy to get on and stay on in the Scarab and the ride as far as harshness on big landings was not any different than landing on my rounded keeled boat.

So I don't think the pad is a big risk as the boat you see in the pics is my old boat and the new owner aka Baronmarine on this site added a small delta pad to it with an Arneson and I have ridden in it at 75 and it rides like on rails.

So the only change would be adding a little longer pad and than multiple steps on the pad to aerate it a bit as an experiment.

This would be for straight line speed and you would not attempt a high speed turn just as you would not attempt it in a properly engineered and proven stepped hull

Indy

Just throw a bigger engine on it, leave the design stuff to the pros (who's boats still spin out) IMO.

tommymonza

Typical answer .As so many on this site add huge power to either a inefficent hull or a deep drive position.

Takes big bucks to build another 200 horse to get another 10 mph when you could spend your own labor and a bit of materials to improve the efficiency of your running surface and drive depth and achieve the same gain.

To be honest I am not in the least bit a fan of stepped hulls as I had ran a splashed Rybo Runner that became these Parasail boats . It handled so bad I told the manufacturers Rep that if it was my boat I was trying to manufacture and sell that i would Grind it up and scrap it and pretend it never existed. Later on they filled in the step in the hull mold and the boat handled predictably.

It was an early single large step and was so sensitive to trim and weight that if a person walked from the stern to the bow the boat would cavitate and bow steer.

I know Step technology has progressed to multiple small steps since and has came a long way since then.

Indy

You asked right? More power will make you go faster, fact. Home made steps, notch, various hull gizmos might make you go faster, might get you in trouble too, worse yet a passenger.

tommymonza

Don't think it would be any more unsafe than many of the guys on here dumping 5 to 600 horses in place of their old 330 horse in a bow steering , stern lifting propped family boat that was never designed to go over 50 mph..

I have years of seat time in these boats and would not push the speed if the boat felt like it might have a handling problem.

Stripped a Mercruiser tiller arm at 60 mph 30 years ago care not to relive a hard instantaneous hard left as that day ended in.Thank God i was on a small calm lake that day and not on Lake Michigan miles out tearing it up in March as I had been the month before.

No passengers, don't need the company.

As you can see from the previous pics the boat only rides on the last 4 feet and outer foot of the keel area as it is now.

Adding a pad has proven to improve handeling as proven in other pad designs .

So what is the big deal of loosening up some of the surface tension of the pad with very small steps or even a surface such as this?

http://travel.cnn.com/lufthansa-tests-shark-skin-881186

You don't think a large area of the very back of a boat floating on a huge volume of aerated water where all the weight and energy is concentrated is dangerous ?

Kinda like injecting water underneath your front tires of your Corvette at 150 to reduce their friction.

tommymonza

My object is not to go a 100 mph. But doing 80 as efficient as I can would be nice. Hell if I could achieve that with 325 horse I might be tempted to slap in a 230 horse 305 stock Merc and run 65 all day long too.

PARASAIL941

Resin and glass are relatively cheap and if you dont like it , grind it off ! Will Smith(Phantom Boats) improved the speed of a Magnum hull without killing the handling ,so if you have the time and ambition , do it. Those Ocean Pro 31's with the step were terrible, We could only make them useable with a 2" drive spacer on the east coast. Good Luck!!

tommymonza

Yea those Ocean Pro's were a trip. Boat would cavitate if someone walked forward so you would naturally trim in to cure it, nope just got worse as the bow buried and created more air under the hull to feed the cavitation.God forbid you get a big gust while flying to the side with a big chute and the boat would practically spinout or you would crash you flyers because you couldn't maintain your 20 mph top speed that the old Seastar 6.9 International Diesels would push ya.

What a bad combination